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Finding the Fourth Proportional to 79.60, 109.86 and 74.72

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Solution

The fourth proportional to 79.60, 109.86 and 74.72 is: 103.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.60 : 109.86 = 74.72 : x
  2. Step 2: Convert to fraction form
    79.60/109.86 = 74.72/x
  3. Step 3: Cross multiply
    79.60x = 109.86 × 74.72
  4. Step 4: Simplify right side
    79.60x = 8,208.74
  5. Step 5: Solve for x
    x = 8,208.74/79.60
  6. Step 6: Final answer
    x = 103.12

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.